Apparatuses and methods of entering unselected memories into a different power mode during multi-memory operation

ABSTRACT

Disclosed are examples of apparatuses including memory devices and systems comprising memories sharing a common enable signal, wherein the memories may be put into different power modes. Example methods for setting the different power modes of the memories are disclosed. In some examples, different power modes may be set by issuing memory group-level commands, memory-level commands, or combinations thereof.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.15/601,792, filed May 22, 2017, which is a continuation of U.S. patentapplication Ser. No. 14/319,302, filed Jun. 30, 2014. This applicationis incorporated by reference herein in its entirety and for allpurposes.

BACKGROUND

Memory systems may include a plurality of discrete memory devices. Eachmemory device may include multiple memories. In some systems, theindividual memories may be referred to as logical units (LUNs). The LUNsmay be organized into memory groups, where each LUN belonging to amemory group receives a common chip enable CE signal. Each memory groupmay contain one or more LUNs. The common CE signal may be utilized tosave layout area and reduce circuit complexity in the memory system byavoiding the need for providing (as used herein, “providing” refers to,for example, generating, issuing, passing, sending, transmitting and thelike) separate CE signals to each of the LUNs of a memory group.

A memory controller in the memory system (which may be external to orinternal to the memory device) may use command and address signalsprovided to the memory devices to command the discrete memories toperform memory operations. Memory operations may include read operationsfor reading stored data from the memories, as well as write operationsfor writing data to the memories to be stored. The memory controllertypically selects a desired LUN in a desired memory group to perform amemory operation, such as reading or writing data to a selected LUN. Thememory controller may provide a logic level low CE signal to the desiredmemory group to activate the LUNs of the memory group. The LUNs mayenter an elevated power mode that readies the LUNs to perform a memoryoperation. Although one of the LUNs will typically be commanded toperform the memory operation, the shared CE signal results in all LUNsin the memory group entering an elevated power mode that draws anincreased current compared to a low power mode.

While the unselected LUNs in the memory group may not be performingmemory operations, the current drawn by the memory group is nonethelessadditive across all of the unselected LUNs, which results in significantpower consumption by a memory group. In configurations having memorygroups with a high number of LUNs, the power consumption for activatingall of the LUNs of the memory group for a memory operation relative tomerely one of the LUNs may be significant.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a memory device according to an embodimentof the invention.

FIG. 2 is a block diagram of a logical unit according to an embodimentof the invention.

FIG. 3 is a block diagram of a memory system according to an embodimentof the invention.

FIG. 4A is a block diagram of a method performed by a memory controlleraccording to an embodiment of the invention.

FIG. 4B is a block diagram of a method performed by a memory groupaccording to an embodiment of the invention.

FIG. 4C is a block diagram of power modes of a logical units indifferent states according to an embodiment of the invention.

FIG. 5A is a block diagram of an additional method performed by a memorycontroller according to an embodiment of the invention.

FIG. 5B is a block diagram of an additional method performed by a memorygroup according to an embodiment of the invention.

FIG. 5C is a block diagram of power modes of a logical unit according toan embodiment of the invention.

FIG. 6A is a block diagram of a further method performed by a memorycontroller according to an embodiment of the invention.

FIG. 6B is a block diagram of a further method performed by a memorygroup according to an embodiment of the invention.

FIG. 7 is a block diagram of a set feature command according to anembodiment of the invention.

DETAILED DESCRIPTION

Certain details are set forth below to provide a sufficientunderstanding of embodiments of the disclosure. However, it will beclear to one having skill in the art that embodiments of the disclosuremay be practiced without these particular details. Moreover, theparticular embodiments of the present disclosure described herein areprovided by way of example and should not be used to limit the scope ofthe disclosure to these particular embodiments. In other instances,well-known circuits, control signals, timing protocols, and softwareoperations have not been shown in detail in order to avoid unnecessarilyobscuring the disclosure. As used herein, apparatus may refer to, forexample, an integrated circuit, a memory, a memory device, a memorysystem, an electronic device or system, a smart phone, a tablet, acomputer, a server, etc.

FIG. 1 illustrates a memory device 100 that includes a memory group 105.The memory group 105 includes four memories 110 a-d, labeled as logicalunits (LUN0-3). Although four LUNs are shown, more or fewer LUNs may beincluded in the memory group. The memory group 105 receives a chipenable CE signal 115 labeled as CEO_n. The CE signal is provided to allof the LUNs 110 a-d in the memory group 105. In other words, it is acommon CE signal. The memory group 105 further includes a communicationchannel 120, labeled as Channel n. The communication channel 120 may bea data bus, which may be used for receiving commands and addresses,receiving data, and sending data. Other signals may also be provided orreceived by the memory group 105 through the communication channel 120.In some embodiments, the memory group 105 may include additionalcommunication channels. Although the memory device 100 is shown with onememory group 105, the memory device 100 may include a plurality ofmemory groups. If the memory device 100 comprises a plurality of memorygroups, the memory device 100 may receive a different CE signal for eachmemory group, and each memory group may have a correspondingcommunication channel.

In some embodiments, when the CE signal 115 is set to a logic level high(e.g., the CE signal is inactive), the memory group 105 may be disabled,that is, all LUNs 110 a-d may be in a first (e.g., low power) mode,referred to as Mode 0. In Mode 0, the LUNs are not at the ready toperform a memory operation, for example, the LUNs may not be able toreceive a signal on the communication channel 120. During the firstpower mode, circuits of the LUNs may be disabled, for example, variousinput and output circuits, timing circuits, memory array circuits, etc.The first power mode Mode 0 may correspond to a standby mode ofoperation in some embodiments. When the CE signal 115 is set to a logiclevel low (e.g., the CE signal is active), the memory group 105 may beenabled and are at the ready to perform a memory operation, for example,receive commands and address signals on communication channel 120indicating the desired LUN to be selected for a memory operation. Forexample, say LUN2 110 c is selected. LUN2 110 c transitions to second(e.g., increased power) mode, referred to as Mode 1. In Mode 1, LUN2 110c is capable of receiving commands on communication channel 120. Duringthe second power mode, circuits of the LUNs are enabled and at the readyfor operation, for example, input and output circuits, timing circuits,memory array circuits, etc. are all enabled. The second power mode Mode1 may correspond to an active mode of operation in some embodiments.

The unselected LUNs (LUN0, LUN1, LUN3) may be transitioned into a third(e.g., an intermediate or low power) mode, referred to as Mode 2.Although the third power mode could be a different power mode than, forexample, the first power mode, in at least some embodiments. The firstand third power modes might be the same power mode (e.g., a standbymode). In one example of a third power mode, a certain subset ofcircuits may be enabled on the LUN. For example, various ones of theinput and output circuits, timing circuits, memory array circuits, etc.are enabled, but the LUN may not be capable of executing all commands.During the third power mode, a portion of the circuits enabled duringthe second power mode, are not enabled, thereby consuming less powerduring the third power mode relative to the second power mode. The thirdpower mode Mode 2 may correspond to an intermediate mode of operation insome embodiments. For example, in some embodiments, Mode 2 draws morecurrent than Mode 0, but less than Mode 1. An advantage of theunselected LUNs transitioning to a third power mode may be a lowercurrent requirement for the memory group 105 than if all of the LUNs inthe enabled memory group entered Mode 1. Furthermore, the time latencyof re-enabling unselected LUNs may be less in Mode 2 than in the firstpower mode, Mode 0. This may improve performance when various LUN on thesame memory group are selected sequentially while the CE signal remainslow. Methods of transitioning the LUNs into the desired power modes willbe described in more detail below.

FIG. 2 illustrates a LUN 200 that may be included in a memory group suchas memory group 105 illustrated in FIG. 1. The LUN 200 may include aninput-output controller 215. The input-output controller 215 may becoupled to a data (DQ) bus 210. The input-output controller 215 mayreceive data, address, and command signals via the DQ bus 210. The DQbus 210 may correspond to the communication channel 120 in FIG. 1. Theinput-output controller 215 may provide memory address signals to amemory array 225 via an address bus 235. The memory address signals aredecoded to identify the memory location of the memory array 225 for thememory operation. The memory array 225 may provide data to and receivedata from the input-output controller 215 via a data bus 230. Theinput-output controller 215 may provide command signals to control logic220 via a command bus 240. The control logic 220 may provide internalcontrol signals to the circuits of the LUN 200 to perform the memoryoperation. The control logic 220 may further provide status signals tothe input-output controller 215 via a status bus 245. The control logic220 may receive a chip enable signal 205 to control activation of theLUN 200. The chip enable signal 205 may correspond to the common enablesignal 115 in FIG. 1. Although not shown, the control logic 220 may alsoreceive command latch enable signals, read enable signals, write enablesignals, and/or additional signals. These signals may or may not beshared with other LUNS that are included in the memory group thatcontains LUN 200. In some embodiments, the I/O controller 215 may bedisabled from receiving input from DQ bus 210 and/or the control logic220 may be disabled from receiving commands from the input-outputcontroller 215 when the LUN is in certain power modes, for example, thefirst power mode, Mode 0.

FIG. 3 illustrates a memory system 300 connected to a host 305. The hostmay be a laptop computer, personal computer, digital camera, mobiletelephone, or other electronic device. The host 305 may interface withthe memory system 300 via a serial advanced technology attachment(SATA), peripheral component interconnect express (PCIe), a universalserial bus (USB), or other interface. The memory system 300 may receivecommand signals from the host 305, and the memory system 300 may providedata signals and/or other signals to the host 305. The memory system 300may include a memory controller 310 and a memory device 335. Thecontroller 310 may be configured to provide signals to the memory device335 to control its operation based on the command, address, data, and/orother signals received by the memory system 300 from the host 305.Although depicted in this embodiment as being external to the memorydevice 335, in other embodiments the controller 310 might be at leastpartially internal to the memory device. The memory device may includetwo memory groups 340, 345. Each memory group 340, 345 may include oneor more memories (LUN_0-N). Although two memory groups are shown, thememory device 335 may include more or fewer memory groups. Likewise,while the memory system 300 is shown including memory device 335,additional memory devices may be included in the memory system 300 aswell. The controller 310 may control the state of chip enable signals315, 325 received by the memory device 335. The number of chip enablesignals may correspond to the number of memory groups included in thememory device 335. The controller 310 and memory device 335 may passaddress, data, and command signals via data buses 320, 330. Each databus 320, 330 may correspond to a memory group 340, 345 included in thememory device 335. The data buses 320, 330 may correspond to respectivecommunication channels for the memory groups 340, 345. In someembodiments, the controller 310 and memory device 335 may pass signalsvia a single data bus. Although only one memory device 335 is shown, thecontroller 310 may control multiple memory devices within the memorysystem 300.

The controller may transition the LUNs to the desired power moderesponsive to selection of a memory group. FIG. 4A illustrates a process400 performed by a controller, for example, the external controller 310,according to an embodiment of the invention. FIG. 4B illustrates aprocess 450 performed by the selected memory group, for example, memorygroup 340 or memory group 345, according to an embodiment of theinvention. The controller may set the common chip enable signal, forexample CEO_n 315, for the selected memory group to a logic level low atstep 405. Once the common CE signal is set to logic level low, thecontroller selects a desired LUN from the plurality of LUNs on thememory group by providing the address of the LUN and a command forselecting the LUN at step 410. Any appropriate LUN addressing systemknown in the art may be used. After sending the select command, thecontroller then issues a memory group-level set feature command at step415. A memory group-level command is issued to all LUNs in a memorygroup, however, the memory group-level command sent at step 415 maydesignate the power mode for the unselected LUNs.

With reference to FIG. 4B, the memory group, such as memory group 340 inFIG. 3 or memory group 105 in FIG. 1, receives the logic level lowcommon chip enable, such as CEO_n 315 or CEO_n 115, at step 455, whichputs the LUNs of the memory group into a second power mode, Mode 1, asillustrated in State 2 in FIG. 4C. Prior to receiving the logic levellow CE signal, the LUNs of the memory group may be in a first power modeMode 0, for example. This is illustrated in State 1 in FIG. 4C. In Mode1, the LUNs may be ready to perform a memory operation. The memory groupreceives the select command and address from the controller and thedesired LUN may be selected at step 460. In some embodiments, the selectcommand may be received by an input-output controller, for example, theinput-output controller 215 in FIG. 2. The select command may beexecuted by control logic in the LUN, for example, control logic 220 inFIG. 2. This is illustrated in State 3 in FIG. 4C. In this example, LUN2is selected. When the memory group-level command is received, allunselected LUNs may be put into a different power mode, such as a thirdpower mode Mode 2 at step 465, as illustrated in State 4 in FIG. 4C.This method may take two address-command sequences to complete: onesequence to select a selected LUN, and another sequence to put theunselected LUNs into a different power mode. When the controller setsthe CE signal for the selected memory group to a logic level high, allLUNs may return to Mode 0, as illustrated in State 5 in FIG. 4C. In someembodiments State 1 and State 5 are equivalent. For subsequent memoryoperations by the memory group, the controller sets the CE signal to alogic level low for the selected memory group, and select and memorygroup-level commands may be issued again by the controller to configurethe power modes of the LUNs of the selected memory group.

FIG. 5A illustrates a process 500 performed by the controller accordingto another embodiment of the invention. The controller may be externalcontroller 310 in some embodiments. FIG. 5B illustrates a process 550performed by the selected memory group, for example, memory group 340 ormemory group 345, according to another embodiment of the invention. Thecontroller may set the common chip enable signal for the selected memorygroup to a logic level low at step 505, the chip enable signal may beCEO_n 315 or CEO_n 115 in some embodiments. Once the common CE signal isset to logic level low, the controller provides sequentially, in otherwords, one at a time, individual LUN-level (rather than memorygroup-level) set feature commands and addresses to each unselected LUNat step 515. In contrast to processes 400 and 450 illustrated by FIGS.4A and 4B, the controller may provide sequentially, individual LUN-levelset feature commands to each unselected LUN at step 515. Each LUN-levelcommand may have an associated address designating the particularunselected LUN.

With reference to FIG. 5B, the memory group receives the logic level lowcommon chip enable at step 555, which puts the LUNs of the memory groupinto a second power mode Mode 1. Prior to receiving the logic level lowCE signal, the LUNs of the memory group may be in a first power modeMode 0, for example. The memory group then receives the individualLUN-level set feature commands and addresses from the controller. Eachunselected LUN is put into a desired power mode, such as a third powermode Mode 2, as each individual LUN-level command is received at step565. In some embodiments, the individual LUN-level commands may bereceived by an input-output controller, for example, the input-outputcontroller 215 in FIG. 2. The individual LUN-level commands may beexecuted by control logic in the LUN, for example, control logic 220 inFIG. 2. This method may take a plurality of address-command sequences tocomplete, based at least in part, on the number of unselected LUNs inthe memory group. However, this method may provide flexibility to puteach of the unselected LUNs into a respective power mode. For example,rather than putting all unselected LUNs into Mode 2, it may be desirablefor unselected LUNs to be put into Mode 0 and/or Mode 1, or some otherpower mode. FIG. 5C illustrates an example of a memory group having LUNsin a variety of power modes. In this example, LUN2 is selected, LUN0 inMode 0, LUN 1 in Mode 1, and LUN3 in Mode 2. When the controller setsthe CE signal for the selected memory group to a logic level high, allLUNs may return to Mode 0. For subsequent memory operations by thememory group, the controller sets the CE signal to a logic level low forthe selected memory group, and individual LUN-level commands may beissued again by the controller to configure the power modes of the LUNsof the selected memory group.

FIG. 6A illustrates a process 600 performed by the controller forexample, the external controller 310, according to another embodiment ofthe invention. FIG. 6B illustrates a process 650 performed by theselected memory group, for example, memory group 340 or memory group345, according to an embodiment of the invention. The controller may setthe common chip enable signal for the selected memory group to a logiclevel low at step 605. The controller may then provide a memorygroup-level set feature command and the address of the selected LUN atstep 610. The memory group-level set feature command may designate thedesired power modes of all LUNs in the memory group. The memorygroup-level set feature command provided by the controller may designatethe address of the memory group, an indication that a memory group-levelcommand is being provided, followed by a set of sub-feature parameters.The sub-feature parameters may provide the address of each LUN in thememory group followed by the desired sub-feature setting, for example,selection status, power mode, or other memory operation setting. In someembodiments, the individual LUN addresses may not be provided in thememory group-level set feature command, and the order that thesub-feature parameters are provided to the memory group designate whichLUN corresponds to the provided sub-feature parameter.

With reference to FIG. 6B, the memory group receives the logic level lowcommon chip enable, for example, the chip enable signal may be CEO_n 315or CEO_n 115, in some embodiments at step 655, which puts the LUNs ofthe memory group into a second power mode Mode 1. Prior to receiving thelogic level low CE signal, the LUNs of the memory group may be in afirst mode Mode 0, for example. The memory group then receives thememory group-level set feature command at step 660 and sets the selectedLUN to Mode 1 and the unselected LUNs to the desired power modes, forexample, Mode 2, based, at least in part, on the sub-feature parameterprovided by the memory group-level command for each respective LUN. Theunselected LUNs may all be set to the same power mode or may be setdifferent power modes, similar to the state illustrated in FIG. 5C. Insome embodiments, the memory group-level command may be received by aninput-output controller, for example, the input-output controller 215 inFIG. 2. The memory group-level command may be executed by control logicin the LUN, for example, control logic 220 in FIG. 2. This method maytake one address-command sequence to execute. When the controller setsthe CE signal for the selected memory group to a logic level high, allLUNs may return to Mode 0. For subsequent memory operations by thememory group, the controller sets the CE signal to a logic level low forthe selected memory group, and a group-level command and address of aselected LUN may be issued again by the controller to configure thepower modes of the LUNs of the selected memory group.

The methods described above are exemplary, and other methods of settingthe power modes of the LUNs may be possible. Furthermore, additionalpower modes may also be possible. For example, a power mode that has acurrent draw between Mode 1 and Mode 2 may be configured. This mode,referred to as Mode 3 may allow a LUN to sniff a data bus. Mode 3 may bedesirable when a LUN is designated as a memory group terminator foron-die termination applications.

FIG. 7 illustrates various signals during a memory group-levelset-feature command according to an embodiment of the invention. Thememory group-level set-feature command may be provided by a controller,such as external controller 310 in FIG. 3. The set-feature command 705is followed by the desired feature 710. An op-code 707 corresponding tothe set-feature command 705 and a feature code 712 corresponding to thedesired feature 710 are provided on a data bus DQ, which may correspondto data bus 210 in FIG. 2 in some embodiments. The set-feature command705 may indicate to the memory group, for example memory group 340 or345 in FIG. 3, that the following feature 710 is to be applied to theentire memory group, not an individual LUN. The set-feature command 705and feature 710 are then followed by one or more sub-feature parameters715. Codes 717 corresponding to the sub-feature parameters 715 areprovided on the data bus DQ. These sub-feature parameters 715 may definethe desired configuration of the LUNs in the memory group, such asLUN0_0-N 340 in FIG. 3. Configurations may include power modes, butother features may also be defined by the sub-feature parameters 715. Aready/busy (R/B#) signal is provided by the memory device to indicatethat the memory device is busy while the features are being set. TheR/B# signal returns to a logic level high upon completion of being set.In some embodiments, the R/B# signal may be provided by control logic,for example, control logic 220 in FIG. 2. Other command-addressprotocols may be used in other embodiments.

Those of ordinary skill would further appreciate that the variousillustrative logical blocks, configurations, modules, circuits, andalgorithm steps described in connection with the embodiments disclosedherein may be implemented as electronic hardware, computer softwareexecuted by a processor, or combinations of both. Various illustrativecomponents, blocks, configurations, modules, circuits, and steps havebeen described above generally in terms of their functionality. Whethersuch functionality is implemented as hardware or processor executableinstructions depends on the particular application and designconstraints imposed on the overall system. Skilled artisans mayimplement the described functionality in varying ways for eachparticular application, but such implementation decisions should not beinterpreted as causing a departure from the scope of the presentdisclosure.

The previous description of the disclosed embodiments is provided toenable a person skilled in the art to make or use the disclosedembodiments. Various modifications to these embodiments will be readilyapparent to those skilled in the art, and the principles defined hereinmay be applied to other embodiments without departing from the scope ofthe disclosure. Thus, the present disclosure is not intended to belimited to the embodiments shown herein but is to be accorded the widestscope possible consistent with the principles and novel features asdefined by the following claims.

What is claimed is:
 1. A method, comprising: receiving a common enablesignal at a first memory and a second memory; in response to the commonenable signal being active, transitioning the first memory and thesecond memory from a first power mode to a second power mode; and inresponse to receipt of a command at the second memory, transitioning thesecond memory from the second power mode to a third power mode.
 2. Themethod of claim 1, wherein a power of the second power mode of the firstmemory is greater than a power of the third mode of the second memory.3. The method of claim 1, further comprising: receiving, at controllogic of the second memory, the common enable signal and an internalcommand, wherein the internal command is based on a received memoryoperation command; and providing, from the control logic, internalcontrol signals responsive to the internal commands and the commonenable signal.
 4. The method of claim 1, wherein the first power mode isdifferent than the third power mode.
 5. The method of claim 1, whereinthe first power mode and the third power mode are the same.
 6. Themethod of claim 1, wherein power of the third power mode is between apower of the first power mode and a power of the second power mode. 7.The method of claim 1, wherein the first power mode and the third powermode include a stand-by power mode.
 8. The method of claim 1, furthercomprising receiving the command on a shared communication channelcoupled to the first memory and the second memory.
 9. The method ofclaim 1, wherein the common enable signal is received from a controller.10. A method, comprising: in response to receipt of an active enablesignal, transitioning a plurality of memories of a memory group from afirst mode of operation to a second mode of operation; receiving aselect command at the memory group to indicate selection of a firstmemory of the plurality of memories; and in response to receipt of agroup-level command at the memory group, transitioning memories of theplurality of memories other than the first memory from the second modeof operation to a third mode of operation.
 11. The method of claim 10,further comprising receiving the active enable signal at each memory ofthe plurality of memories.
 12. The method of claim 10, furthercomprising receiving the group-level command at each memory of theplurality of memories.
 13. The method of claim 1, wherein the firstpower mode is different than the third power mode.
 14. The method ofclaim 10, wherein the first power mode and the third power mode are thesame.
 15. The method of claim 10, wherein power of the third power modeis between a power of the first power mode and a power of the secondpower mode.
 16. The method of claim 10, further comprising transitioningthe plurality of memories to a standby mode of operation prior toreceipt of the active enable signal.
 17. The method of claim 16, whereintransition of the plurality of memories to the standby mode of operationis in response to receipt of an inactive enable signal.
 18. The methodof claim 17, further comprising receiving the inactive enable signal ateach memory of the plurality of memories.
 19. The method of claim 10,further comprising enabling an input-output circuit of a memory theplurality of memories based on a transition to the first mode ofoperation.
 20. The method of claim 10, further comprising disabling aninput-output circuit of a memory the plurality of memories based on atransition to the second mode of operation.